Why does Unsharp Mask add 500-1000% time to the export process?

[Grant5C25]

I almost never use unsharp mask because it adds a ridiculous amount of time to my exports.  The same computer sharpening with multiple different sharpening nodes in Davinci Resolve barely ads ANY time to the export let alone exponentially increasing the time to export 2-4 degrees.  I'm at about 10 minutes for a 30 second clip with Unsharp Mask and about 30 seconds for the same clip without Unsharp Mask.  Crazy.

Computer:

Core i7 8700k, 32GB Ram, Windows 10 x64, Nvidia GTX 1080 8GB

[Robert Shultz]

That is a long time but it does take a lot of processing for that effect.

[basil1891 · Accepted solution]

Unsharp mask in PP is not gpu-accelerated, it's a 'CPU-effect'. What even worse - it's single threaded. Also, you may add this bug to the mix: Order of filters/effects and drop in CUDA-rend... - Adobe Support Community - 10510537

Hence your got the "speed".

[Grant5C25]

Damn - I thought for sure UM was GPU accelerated.  That seems like an oversight to not make a very taxing process gpu accelerated.  Anyways - just tested it.  Against my better judgement I sharpened before my other adjustment layers and export went from 4:54 for my clip to 1:43.   Thanks!!!